GIANT ROBOTS SMASHING INTO OTHER GIANT ROBOTS

Written by thoughtbot

How Grep Got its Name

How did grep get its name? This all starts back with ed, the original unix editor. ed was a command-line editor that worked identically to the colon-commands in vi and vim–in fact, you can press Q to get into ed mode (then type vi to get back into vim). From the ed editor you can issue common line-oriented commands like s, d, y, and so on:

:%s/rdoc/docr/g
:/include/d

Mr. Ed giving a speech

If you're following along at home you may wonder "how can I see the contents of this file?" Well if you just want to see every line you can use %p (% is "the whole file", and p is "print to screen"), though it's more likely that you want to see a small series of lines. 10,20p will show you lines 10 through 20, but maybe it makes more sense to see all lines matching a regular expression.

From ed, to see all lines matching "include", use g/include/p. To see all lines matching "docr" use g/docr/p. In general, to see all lines matching the regular expression "re", use g/re/p.

… And that's how grep got its name.

What's next?

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